Paraffin scraper



J. A. SMETHERS PARAFFIN SCRAPER FledAug. 24. 1940 Sept. 8,' 1942.

Patented sepas, 1942- UNITED STAT ranarrniscnsrnn James A. Smethers; Odessa, Tex. :j Application August 24, 1940, Serial No. 354,053

'1 claims. wl. 'isc-1s) This invention relates toa tool for cleaning oil wells. More particularly it relates to a tool for scraping material, such as paraflin, from the tubing or casing in an oil well.

As is` well understood, in the production of parain base oils, a portion of theV parailin is deposited on the walls of the casing or tubing through which the oil is produced, thu's graduallyY reducing the eilectivecross section'of the tubing through'which the oil must pass, and possibly eventually blocking the tubing entirely. This results in a reduction of the output of the well, or even a complete cessation thereof.v

It is an important objectof `the present invention to provide animproved tool for removing such accumulation of parailin from the well tubing. i

tubing. The tool includes a plurality of cutters,

' or spinners, 5, 6, 'I and 8, mounted on along stem or mandrel 9, which is providedwith a threaded pin III 'at its upper end, by means of which the tool is attached to a cable Il or other suitable means known to the art for raising and lowering the tool in the well. This means may include a sinker bar to ensure the downward passage of the toolI in the well.

Mandrel 9 is shown as having a conventional square portion I2 to accommodate a wrench adjacent pin I0 to assist in removing or attaching \It is another object of this invention toprovide a tool for this purpose which acts to break the parain into small pieces, so that -it'wlll pass more readily from the-tubing. l

It is still another'objectof this invention to provide such a tool having a.r plurality of cutters, the cutters being capable of acting independently of each other. e

It is a still further object of this invention to provide such a tool capable of striking a blow on the cutters, or acting as a jar, to loosen the cutters or the parailin into which they may have been forced.

This inventionpossesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of the invention. For this purpose there is shown a form in the drawing accompanying and forming part of the present specication. This form'- will now be described in detail, illustrating the general principles of 'the invention; but it is` to be understood thatr this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claims.

In the drawing: Figure 1 is an elevation of a the invention;

' Fig. 2 is an elevation showing the tool as being lowered into` the well tubing;

Fig. 3 is a detail of one of the cutters on Van enlarged scale; and Fig. 4 is a cross section of Fig. 3.

Referring to the drawing, Figs. 1 and 3 illustrate the parts of the tool in the relative positions which they occupy wherrthe tool is suspended or running in tubing where noparailin or the like is encountered, or when being pulled from the the tool from vor to the cable. Below the wrench square Il an annular shoulder I4 is formed. Axially spaced-along mandrel 9 isl a plurality o f stop collars I5, the'lower ,end of each of which forms an annular shoulder I6, the upper end of each being provided with ratchet teeth, as' I1, I8. The lower en d of the mandrel is provided with a similar collar I3 which however has substantially nat lower face, an'd an upper annular shoulder with ratchet teeth 20, similar to those on collars I5.

Cutters 5,- 6, 'I are similar,differing only in their outside diameters, hencev only one of them, for example cutter 6, will be described. Referring to Fig. 3, it will be noted that the cutter includes a central tubular portion, or long hub 2I which is freely slidable as well as rotatable on -'mandrel 9. The upper end of hub 2| has an an- 'Y like or spiral,V formation.

tool embodying The lower cutter 8 d iiers from the cutter described and shown in Fig. 3 in that its hub 26 extend beyond theflower end of hub 2B and are joined together forming a point 28. The lower -end of hub 26 has ratchet teeth 29 for cooperation with the teeth 2U on collar I9. Collar I9 is accommodated in a space 30 provided within blades 2l below hub 26.

The wings of adjacent cutters have helices of opposite hands; thus-the helix of the Wings of cutters 5 and lare left handed, While the helix of the wings 25 ofcutter B, which is between cutters 5nd "I is right handed. SimiIarly the helix of wings 21 of cutter 8 is right handed. Further, as clearly shown in Fig. l, the outside diamueter of the cutters 5,6, l and 8 decreases progressively toward the lower end of thetool. I, at the top of the tool, has an outside diameter over the wings which approximates the inside diameter of the tubing Il in which the tool is to operate, a working clearance being provided, while cutter I is the smallest.

In this way the work to be done and the stress is more or less evenly distributed among the several cutters.

As previously mentioned, the paraiiln collects on the -wall of the tubing through which the oil is produced. Such-acondition is illustrated in Fig. 12, wherein a layer of paraln is indicated by l2 on the inside of tubing 3|-,

As the tool is lowered into the well tubing 3|, the cutters l, C, 'I and 8 are in their lower positions, that is supported on their respective collars with the ratchet teeth engaged, as shown in Fig. 1. When the cutters encounter the parailln layer 32, their downward movement is retarded, the mandrel 9 however continuing to move downwardly. When the shoulders I6' of the stop collars I engage the surfaces 22 of the cutters, the.

continued downward movement of the mandrel forces the cutters downwardly through the parafiln, and since the cutters'are free to rotate on mandrel 9 the wings 25 of the cutters form spiral cuts in the paramn. vSince the spiral cuts formed by adjacent cutters are of opposite hand, the parailln is very effectively cut into small pieces. When the mandrel 9 is moved upwardly, the cutters moved outwardly with respect thereto into their original positions of Fig. l with their ratchet teeth engaging those of the respective stop collars. This prevents rotation oi' the cutters on the upward stroke and causes the cutter wings 25 toscrape the parailln from the tubing. Since the parailln was cut or broken on the downward stroke of the tool, it is removed from the wall in small pieces which are readily removed from the well.

'I'he forces tending to rotate the tool by the cutters on the up stroke are practically balanced, since the wings on adjacent cutters have spirals in opposite directions. Further, the inertia of the cable o r other means supporting the tool, also opnoses such rotation.

It may sometimes happen that the parailln extends entirely across the bore of tube 3|. AIn this case the point 28 of the lower cutter will readily pierce it, enabling the tool to be lowered j without difficulty.

It is intended that the scraper be spudded or worked up and down in short strokes in a portion of the well until the parain is scraped from the wall of that portion. The tool is then lowered and the operation repeated in the next lower portion. With the cutters embedded in theparaiiln, as shown in Fig. 2, it is possible to strike a blowon the bottoms of the cutters by rapidly moving the mandrel up. Such a jarring blow assists in breaking up the parailin and is useful in loosening the cutters if they happen to stick. By this method the well or tubing is cleaned for its 'entire length without the need oi removing the tool until the cleaning is completed.

What is claimed is:

'1.In a cleaner adapted for use in a well, a mandrel, a plurality of axially spaced cutters on the mandreLsaid cutters being slidable as well as rotatableon the mandrel,- stop collars -secured Thus, cutter,

cutter when said cutter engages the face, each of said cutters including wings adapted to impart rotation to the cutter as the cutter is moved axially through the well, said wings being so arranged that the rotation imparted to adjacent cutters is in opposite directions.

2. In a cleaner adapted for use in a well, a mandrel, a plurality of axially spaced cutters on themandrel, said cutters beingslidable as well as rotatable on the mandrel, means to limit the axial movement-of the cutters on the mandrel as well as to prevent rotation of the cutters in-'one direction, each oi' said cutters having wings adapted to cause rotation of the cutter as the cleaner is moved through the well, the outside diameter of the top cutter being substantlally the same as the inside diameter of the well tubing to be cleaned, the outside diameter oi the succeeding cutters being progressively less than that of the-top cutter.

3. In a well cleaner, a stem arranged for axial movement in the well, a plurality oi cutters mounted on the stem in axially spaced relationship, said cutters being arranged for limited axial movement on the stem, the cutters also being rotatable on the stem, means whereby the cutters are held against rotation at one end of their axial movement, each of said cutters having -a plurality of helix-like wings, the helices of the wings on adjacent cutters being of opposite hands.

4. In a well cleaner, a mandrel arranged for longitudinal movement in a well, axially spaced cutters on the mandrel, adjacent cutters being separated by a space approximating the length of a cutter, said .cutters being slidable axially as well as rotatable on the mandrel, means to restrict the axial movement as well as to restrain the rotary movement of the cutters with respect to the mandrel, each of said cutters having spiral 'wings adapted to rotate the cutter upon axial movement of the cutter in the well,.the wings on saidcutters being so arranged as to cause adjacent cutters to rotate in opposite directions in response to said axial Imovement, the means to restrict the rotary movement acting at one extremity of the axial movement of the cutter with respect to the mandrel to oppose the rotative force of the wings.

5. In a well cleaner, a mandrel, cutters rotatably supported on the mandrel for axial movement therealong, means to limit the axial movements of the cutters with rrespect to the` mandrel to substantially equal amounts, wings on each of said cuttersadapted to rotate adjacent cutters in opposite directions in response to axial movement of the cutters in the well, and means to restrict relative rotation between the cutters and the mandrel at one extremity of the axial movement of the cutters with respect to the mandrel.

6. In a well cleaner, a mandrel arrangedv i'or longitudinal movement in a well, axially spaced 4- cutters on the mandrel, said cutters being axially to the mandrel between adjacent cutters to limit face thereof adapted to prevent rotation of a slidable as well as rotatable on the mandrel, and having progressively smaller outside diameters towardthe lower end of the mandrel, means carried by the cutters adapted to rotate adjacent cutters in opposite directions upon axial movement of the cutters in the well, means carried' by the mandrel between adjacent cutters to limit axial movement of the cutters, said means including ratchet teeth for cooperation with one of said adjacent cutters to restrict rotation of said one cutter to one direction.

'7. In a well cleaner, a mandrel arranged for longitudinal movement in a vvll, axially spaced liub'at its upper end. there being a. space in said rotatable cutters on the mandrel, said cutters cutter between said'hub and the point, said manalso being axially slidable onvthe mandrel and drel extending ,through said hub vand having a.

having successively smaller outside diameters tocollar in said space for engaging the -lower vsurward the lower end of the mandrel, the lowelr- 5 face of saidphub and supporting the cutter. most cutter terminating in a point and having a JAMES A. SMETHERS. 

